A seemingly paradoxical mortality pattern occurs between elderly African Americans (AA) and European Americans (EA). Until age 70, the all-causes death rate in AA is as much as 50% higher than that of EA. After seventy years of age, a crossover in all-causes mortality has been described, where the EA death rates are reversed in favor of AA. Conventional risk factors cannot explain this crossover. Clinical studies have shown a strong correlation between comorbidity and mortality for several index conditions. This research proposes to examine race differentials in morbidity and mortality among the elderly. Specifically, it begins to deal with how comorbidity might explain AA/EA differences in mortality at older ages. This study is based on a cohort of 3,000 subjects aged 65 and over, who were members of the Kaiser Foundation Health Plan in 1980. Nine years of follow-up (from 1980-1988) was performed using medical records. Comorbidity status has been determined by evaluating each subject for the presence of any of 33 prevalent and incident conditions. Analysis will examine the influence of cormorbidity on AA-EA differences in mortality. Further analysis will examine the influence of important co-existing conditions such as hypertension, diabetes, and ischemic heart disease on the race-by-age differences in mortality.